1. Technical Field
Embodiments of the present invention relate to a fan. More particularly, embodiments of the present invention relate to a vibration fan.
2. Description of Related Art
In order to enable easy carrying of portable devices, portable devices are being developed having configurations that are increasingly lighter and thinner. Because the physical size of portable devices is getting smaller, the demands for heat dissipation are increasing. Therefore, heat dissipation technology is an important field.
A portable device generally employs a centrifugal fan to dissipate heat. A blade of the centrifugal fan rotates in a flow channel, and consequently generates air flow and also directs the air flow towards a ventilation orifice, thereby dissipating heat to the external environment by heat convection.
However, although the centrifugal fan can effectively generate and direct air flow to dissipate heat, the rotating blade generates an annoying noise. Further, minimizing the size of the centrifugal fan is not easy because a bearing and a rotating blade are necessary elements therein, and therefore, the centrifugal fan may impede miniaturization of the portable device. Still further, if the height of the bearing of the centrifugal fan is reduced in an effort to minimize the size of the centrifugal fan, the strength of the bearing may be decreased, and hence, the bearing may be damaged easily, thereby reducing the life of the centrifugal fan.
Some manufacturers utilize piezoelectric fans to dissipate heat, such as the piezoelectric fan disclosed in U.S. Patent Publication No. 2010/0150753 and entitled “Oscillating Diaphragm Fan Having Coupled Subunits and a Housing Having an Oscillating Diaphragm Fan of this Type.” Typically, a piezoelectric fan has to provide a high voltage to deform the piezoelectric material, so as to agitate air and generate air flow. If the piezoelectric fan is installed in a portable device, a considerable amount of power may be consumed, resulting in draining of the battery in a short time. Therefore, the piezoelectric fan is not suitable for use in a portable device.